%%%------------------------------------------------------------------------------------------------------------
\begin{footnotesize}
$$
\begin{smallmatrix}  \underbrace{
    \left\{
        \begin{smallmatrix}
            \left(
            \begin{array}{cccc}
             1& 0 &0 \\
             0& 1 &0 \\
             0& 0 &1
            \end{array}
            \right )
            \cdots
            \left(
            \begin{array}{cccc}
                1& 0 &0 \\
                0& 1 &0 \\
                0& 0 &1
            \end{array}
            \right)
        \end{smallmatrix}
        \right\}
     }\\5
\end{smallmatrix}
\times
\begin{smallmatrix}
\left[
    \begin{array}{cccc}
    1\\
    1\\
    1
    \end{array}
\right ]
\end{smallmatrix}
=
\begin{smallmatrix}  \underbrace{
    \left\{
        \begin{smallmatrix}
            \left(
            \begin{array}{cccc}
             1 \\
             1 \\
             1
            \end{array}
            \right)
            \cdots
            \left(
            \begin{array}{cccc}
                1 \\
                1 \\
                1
            \end{array}
            \right)
        \end{smallmatrix}
        \right\}
     }\\5
\end{smallmatrix}
$$
\end{footnotesize}
%%%------------------------------------------------------------------------------------------------------------

